“ This is Simosuchus. It's not a dinosaur, but a miniature relative of crocodiles, one that lives almost entirely on land, and is strictly vegetarian. ”
Simosuchus (Pug-nosed Crocodile) is a genus of terrestrial notosuchian crocodylomorph that lived in the Maevarano Formation of the Mahajanga Province (known as "Majunga" in French) in northwest Madagascar, 70 - 66 million years ago, during the Maastrichtian stage of the Late Cretaceous Period, peculiar for its herbivorous diet and adaptations implying that it may have been capable of digging burrows (although it is not specialized for a lifestyle primarily focused on burrowing).[3][DN 1] A single multicuspid tooth found in the Kallamedu Formation of the Kaveri Basin indicates the presence of Simosuchus (or a similar-looking close relative of it) in southern India.[1]
Simosuchus is a terrestrial crocodylomorph that grew to the size of a small dog, with adult specimens being around 75 centimeters (2 feet, 6 inches) long.[2] Like other crocodyliforms, it was protected by tightly-interlocked deposits of bone, with the osteoderms that armor the back, tail, and limbs being light and porous, while those that cover the belly are plate-like, with an inner structure resembling that of cancellous (spongy) bone. Unlike most crocodyliforms, however, Simosuchus has a short tail and, as opposed to having the long, low skulls and conical teeth of other crocodyliforms, it has a snout that is short in terms of length yet tall (hence its name, "pug-nosed crocodile"), filled with multicuspid, maple leaf-shaped teeth, with at least 45 autapomorphies (features unique to the animal) found in its skull alone. It is believed that one factor in the evolution of Simosuchus is "paedomorphosis", growing in such a way that it gains or retains features that are usually only found in juveniles.[3]
Because its complex teeth resemble those of modern-day vegetarian iguanids, ornithischian dinosaurs like some ornithopods, stegosaurs, and ankylosaurs, as well as other plant-eating reptiles, paleontologists believe that Simosuchus is primarily - if not exclusively - herbivorous, being among the last of many herbivorous crocodyliforms that evolved during the Mesozoic Era.[3][4] Consequently, due to its plant-eating adaptations, the short, blunt snout of Simosuchus cannot bite as hard or as fast as the powerful jaws of other crocodyliforms, as it no longer had the need to capture and subdue other animals.[3]
To escape a Majungasaurus, several Simosuchus escape to burrows they dug beforehand in the parched lands of Madagascar
“ The island of Madagascar has been separated from the African mainland for 80 million years, so long that most of its animals are now very different from any to be found elsewhere. ”
Simosuchus lived 70 - 66 million years ago in the Maevarano Formation in the Mahajanga Province of Madagascar, an island on a tectonic plate of the same name that split away from Africa approximately 170 - 155 million years ago, then separated from the Indian subcontinent around 90 - 80 million years ago.[5][6] The Maevarano Formation is recognized as an alluvial plain where the discharge of rivers fluctuate. The area is also believed to have had reddish soil, with floodplains that supported vegetation able to grow in the relatively dry climate. The region, at times semi-arid (like it is today), at times undergoing strong dry and wet seasons, was eventually claimed by rising sea levels that pushed the shoreline back. This may or may not have been the result of the Cretaceous-Paleogene Extinction Event, a catastrophe that wiped out three-quarters of life on Earth.
A single, isolated multicuspid tooth found in the Kallamedu Formation of the Kaveri Basin in southern India indicates the first known presence of Simosuchus or a similar-looking notosuchian outside of Madagascar, serving as further evidence of the link between India and Madagascar.[1]
Social Behavior, Evasive and Defensive Tactics[]
Prehistoric Planet depicts Simosuchus as having social capabilities, able to form small groups, based on how numerous specimens are found together, and how its living relatives were, to a degree, social.[DN 2]
A Simosuchus tucks itself deep into its burrow, presenting nothing but its heavily-armored back to threats outside
“ The Simosuchus have a network of escape routes that lead them to their underground burrows. Once inside, they block the entrance with their heavily-armored backs. ”
Simosuchuses are shown to have prepared narrow escape burrows in which they can hide in the event of a predator attack, plugging the entrances with their heavily-armored backs. For a little more security, they can dig even deeper into their burrows to ensure that those hunting them really cannot reach them. Contrary to older studies, Simosuchus is not fossorial (specially adapted to digging and living primarily - but not solely - underground), as its large, wide head is too broad for burrowing head-first (by contrast, modern head-first burrowers have narrow heads with a shovel-like "dorsoventrally narrowed cutting edge"). Furthermore, its large eye sockets, lower jaws, and teeth cannot withstand the stresses, loads, and forces associated with burrowing, while its upper jaw has no adaptations for keeping its mouth shut when digging through the ground. Nevertheless, Simosuchus may have occasionally used its snout to aid its limbs in scratching and digging burrows, just like how modern crocodiles dig complex tunnels several meters in length despite not being fossorial; Chinese alligators can, for instance, make extensive and elaborate underground mazes extending more than 50 meters (164 feet) in length, with several entrances, rooms, and even water pools. And just as how Chinese alligators can retreat into their labyrinths to escape from the extreme heat of summer days and undergo brumation (the reptile equivalent of hibernation) during winter, Simosuchuses can also take refuge in their burrows to rest safely (and perhaps even stay dormant for extended periods of time), allowing them to survive the unforgiving conditions of the Maevarano Formation.[3][7][DN 1]
Should a Simosuchus be unlucky to find no vacant burrow to jump into while being pursued by a hunter, it can buy time to escape by bluffing in the form of aggressive hisses, tail swipes, kicks, and even running and sliding backwards into predators without actually intending to make contact, for it is reasonable to assume that, while not indicated in the fossil record, Simosuchus and other extinct creatures were likely as complex as animals today.[DN 3]
Filming Location Lower Zambezi National Park, Lusaka Province, southeast Zambia[PhP 1]
One Simosuchus steps on another to feed on vegetation beyond its reach
In the third segment of Islands, on Madagascar, a Simosuchus navigates through an area of plants. It is then shown that they live in a group. One Simosuchus reaches up to grab leaves that are out of reach by rearing up and standing on top of another, while some members of the group are shown simply basking under the sun, or sleeping in the shade, not too wary of hunters given how their heavily-armored bodies make them feel more secure, unaware that, from afar, the region's apex predator is observing them.
A female Majungasaurus stands in the distance, preparing to ambush and grab a Simosuchus
“ Majungasaurus. Madagascar's top hunter. This particular female is blind in one eye. So she finds it hard to make a kill, and is now very hungry. ”
The hunter, a female Majungasaurus appears to have dried blood and various wounds on her, and it is revealed that her left eye has gone blind. Due to her disability, she has found it difficult to hunt, and has thus gone very hungry. She finally decides to charge at the group of Simosuchus, causing them to run for the burrows they set up beforehand to escape from predators. One male Simosuchus ends up unable to find an unoccupied burrow, and is left to face the Majungasaurus.
A male Simosuchus charges backwards, keeping the Majungasaurus at bay until he can find a way to escape
“ This little male is unlucky. But he's not helpless. Reverse charges, tail swipes, and aggressive kicks. ”
With nowhere to run, the Simosuchus resorts to bluffing his way out of the situation, with reverse charges, kicks, hisses, and tail swipes, confusing and deterring the Majungasaurus long enough for the notosuchian to find a vacant burrow to rush for and hide in. The hunter tries to reach into the burrow, but it proves too narrow for her broad snout to fit in. As a safety precaution, the Simosuchus digs himself even deeper, getting dirt all over the hunter's face.
Once he is sure that the Majungasaurus is gone, the Simosuchus exits his burrow
“ The hunter's snout is too broad to reach very far inside. But just to be on the safe side, the Simosuchus digs even deeper. For the Majungasaurus, yet another hunt has ended in failure. ”
Dejected and left growling in frustration due to the failure to secure a meal, the Majungasaurus walks off. Once the hunter has left, the Simosuchus warily walks back out of his burrow, looking around to make sure there are no other threats around before moving on.
Gallery[]
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